user/src/com/google/gwt/user/Popup.gwt.xml

<!--                                                                        -->
<!-- Copyright 2006 Google Inc. All Rights Reserved.                        -->
<!-- Deferred binding rules for browser selection.                          -->
<!--                                                                        -->
<!-- This module is typically inherited via com.google.gwt.user.User        -->
<!--                                                                        -->
<module>
	<inherits name="com.google.gwt.core.Core"/>
	<inherits name="com.google.gwt.user.UserAgent"/>

	<!-- Fall through to this rule is the browser isn't IE -->
	<replace-with class="com.google.gwt.user.client.ui.impl.PopupImpl">
		<when-type-is class="com.google.gwt.user.client.ui.impl.PopupImpl"/>
	</replace-with>

	<!-- IE has a completely different popup implementation -->
	<replace-with class="com.google.gwt.user.client.ui.impl.PopupImplIE6">
		<when-type-is class="com.google.gwt.user.client.ui.impl.PopupImpl"/>
		<when-property-is name="user.agent" value="ie6"/>
	</replace-with>
</module>